Know precise definitions of angle, circle, perpendicular line, parallel line, and line segment, based on the undefined notions of point, line, distance along a line, and distance around a circular arc.

Make formal geometric constructions with a variety of tools and methods (compass and straightedge, string, reflective devices, paper folding, dynamic geometric software, etc.). Copying a segment; copying an angle; bisecting a segment; bisecting an angle; constructing perpendicular lines, including the perpendicular bisector of a line segment; and constructing a line parallel to a given line through a point not on the line.

Do Now

5 minutes

As students walk in the room, I have them write descriptions of the undefined terms "point," "line," and "plane." This is a review from the first lesson in the unit. After about three minutes, we discuss their descriptions and why the terms are called "undefined." This leads students into the next section where they practice various constructions.

Activity

Students review and practice the various constructions from throughout the unit. Since we have already spent time on the constructions, we do not go over them together, unless students need a refresher. The majority of students are able to perform the constructions without my help. When students do need help, I pair them with another student who is able to help his or her partner with the construction. Additionally, I have the students refer back to their notes to help them when they are stuck.

Constructing Quadrilaterals with Geometer's Sketchpad Activity.pdf

Geometric Constructions Unit Review.mov

Summary

5 minutes

At the end of the lesson, we go over the worksheet. I ask a few students to show their constructions on the document projector. We discuss the accuracy of the constructions and correct any errors the students have made.